Topic: 2 Oil Orifices or 4, that is the question

[corkman]

I have a question:
On my 1978 CB750K I see what appear to be 4 oil orifices on the head. The two inside ones have holes in them for oil to flow but the two outer orifices do not appear to have holes in them for oil to flow. Is this normal, or do I need to open the holes up?

Thanks,
Bill

[joeb]

Are you talking about the two that supply oil to the head ,if so there should only be two if I am correct. o-rings  go in the other spots.

[oldfart]

On a 750, two head passages are not drilled, but o-rings go in all four because there are four cam tower oil passages.  Without the outer o-rings pressure will drop.  The cam towers are made to be swappable left for right, is why they are drilled all four.